>>538813561
>Did they come up with the space travel and mother wisp plot?
No.

>or did they just write the dialogs
Yes. Dialogue only. Actually, the dialogue was already written. Pontac and Graff joined Colors development late, the Japanese script was already fully done. Pontac and Graff wrote the English localization

>while providing some participation to the plot?
Pontac and Graff said Sonic Team wanted to get rid of Orbot and Cubot, but Pontac and Graff insisted to keep them and convinced Sonic Team. It's unclear if they were talking about Colors or Lost World though

Yasushi Otake wrote the story of Sonic Colors. Pontac and Graff wrote the English script. I don't know if Pontac and Graff had anything to do with the dialogue in the DS version. The Japanese version and the DS version are more in character from what I know, so my guess is no

>>538813852
I'm glad he was. I like his passion and confidence, and that's something that's been missing from the series